Silicone resin composition for encapsulating luminescent element and process for producing optical-semiconductor electronic part with the same through potting

Abstract

The present invention provides a silicone resin composition for encapsulating light-emitting elements with which encapsulation using a potting method can be easily accomplished, and which can be easily molded into a lens shape such as hemisphere, parabola, or the like. The composition can impart high transparency to the resulting encapsulating lens molded using a potting method. More particularly, the invention provides a silicone resin composition for encapsulating light-emitting elements, including 2 to 25 wt % of silica with a mean particle size of 1 to 30 nm based on the total amount of Components (A) and (B); and having a viscosity (23° C.) of more than 10 Pa·s and less than 70 Pa·s, and a thixotropic index of 2.0 to 5.5; the composition being used for encapsulation using a potting method. The invention also provides a process for producing an optical semiconductor electronic part, including applying the composition as an encapsulating resin to a substrate with a light-emitting element, thereby molding the encapsulating resin into a lens shape by potting.

1. A silicone resin composition for encapsulating light-emitting elements consisting essentially of:
 (A) a liquid or solid organopolysiloxane having at least two alkenyl groups per molecule represented by Average Compositional Formula (1):
   R n SiO (4-n)/2   (1)
 
 
 
       wherein each R is independently a substituted or unsubstituted monovalent hydrocarbon, alkoxy, or hydroxy group; 0.1 to 80 mol % of R which is a substituted or unsubstituted monovalent hydrocarbon comprises alkenyl groups; and n is a positive number that satisfies 1≦n<2;
 (B) an organohydrogenpolysiloxane having at least two Si—H bonds per molecule represented by Average Compositional Formula (2):
   R′ a H b SiO (4-a-b)/2   (2)
 
 
 
       wherein each R′ is independently a substituted or unsubstituted monovalent hydrocarbon excluding an aliphatic unsaturated hydrocarbon; and a and b are each positive numbers that satisfy 0.7≦a≦2.1, 0.001≦b≦1.0, and 0.8≦a+b≦2.6; and/or
 an organohydrogensilane represented by Formula (3):
   R′ c SiH (4-c)   (3)
 
 
 
       wherein each R′ is as defined above, and c is 1 or 2; and
 (C) an addition reaction catalyst; 
 the composition further comprising (D) 2 to 25 wt % of silica with a mean particle size of 1 to 30 nm based on the total amount of Components (A) and (B); the composition having a viscosity (23° C.) of more than 10 Pa·s and less than 70 Pa·s, and having a thixotropic index of 2.0 to 5.5; and the composition being used for encapsulation using a potting method. 
 
     
     
       2. The composition according to  claim 1 , wherein the silica has a mean particle size of 1 to 15 nm. 
     
     
       3. A process for producing an optical semiconductor electronic part, comprising applying the composition of  claim 1  as an encapsulating resin to a substrate with a light-emitting element, thereby molding the encapsulating resin into a lens shape by potting. 
     
     
       4. A process for producing an optical semiconductor electronic part, comprising applying the composition of  claim 2  as an encapsulating resin to a substrate with a light-emitting element, thereby molding the encapsulating resin into a lens shape by potting.